The microelectromechanical systems (MEMS) switch has become an essential element in many electronic systems and would find even greater usage in integrated circuit and other electrical applications, except for its fundamentally electromechanical nature and thus excessively limited operating lifetime. The fundamental mechanical limitations of wear, stiction and thermal response as well as electrical resistance, R, increases and other mechanical related properties are clearly present in these small switches to a degree, currently precluding use of such elements except in well defined and probably mostly non-critical switching applications. MEMS lifetimes measured at 109 and upward operating cycle events would clearly increase the use of such switches to a significant degree.
Thus even though the electrical switching art reveals a considerable degree of direct approach attention to the improvement of MEMS switches over the years, there appears to exist in this art a degree of avoidance of one indirect approach to the improvement of many of the MEMS encountered fundamental mechanical limitations. This indirect approach involves the use of lubrication for the switch elements, especially lubrication with materials having more than friction related improvement capabilities, modern materials able to also contribute to a plurality of electrical characteristics of a treated switch.
Previous lubricant based attempts to realize increased lifetimes have included the addition of self-assembled monolayer (SAM) lubricant materials, including materials derived from diphenyl disulfide and other lubricants, to MEMS contacts. Such additions provide less than desired performance often because of carbonaceous film growth and contact resistance difficulties encountered in the range of 104 operating cycles with, for example, 10 microamperes of load current and from heat promoted failures incurred very early in the presence of one milliampere load currents. Improved lubrication involving nanoparticles in combination with plasma is the domain of the present invention.
Nanoparticles in general are considered in the World Intellectual Property Organization (WIPO) published patent application 2006/110166 of E. P. Giannelis et al. of Cornell University. This application designates the United States as one of several locations in which patent protection is sought. The application is titled “Functionalized Nanostructures with Liquid-Like Behavior” and is hereby incorporated by reference herein. The work leading to this application was also supported by the U.S. Air Force.